Through wall installation of sensors in fuel tanks

Abstract

The present invention provides a sensor assembly for installation within an opening in a wall separating an interior cavity from an exterior. The sensor assembly includes an exterior housing and a cartridge including a sensor. When the cartridge is correctly positioned within the housing, a flow path is established from the interior cavity to the sensor supported within the cartridge. When the cartridge is not positioned within the housing, the flow path is blocked.

What is claimed is: 
     
       1. A sensor assembly for installation within an opening in a wall separating an interior cavity from an exterior, the sensor assembly comprising:
 a housing including an interior space, the housing configured to be received within the opening in the wall such that at least one housing aperture in a wall of the housing communicates with the interior cavity, wherein the housing aperture is configured such that:
 a flow path through the housing aperture between the interior cavity and the housing interior space is blocked when a cartridge is not positioned within the housing interior space; and 
 the flow path through the housing aperture between the interior cavity and the housing interior space is established when the cartridge is positioned in a flow position within the housing interior space; 
 
 the cartridge configured to be received within the housing and including:
 a sensor supported within a central recess of the cartridge and disposed within the housing interior space when the cartridge is positioned within the housing interior space; and 
 at least one cartridge aperture positioned such that a flow path through the cartridge aperture is established between the housing interior space and the sensor when the cartridge is positioned within the housing interior space; 
 
 a base retaining device configured to retain the cartridge within the housing; and 
 a stator disposed within the housing and rotatable between a closed position and an open position, the stator including:
 a central cavity; and 
 a stator aperture through a sidewall of the stator, the stator aperture located such that:
 in the open position, the stator aperture is in alignment with the housing aperture such that a flow path is established between the interior cavity and the stator central cavity; and 
 in the closed position, the stator aperture is out of alignment with the housing aperture such that the flow path between the interior cavity and the stator central cavity through the stator aperture and the housing aperture is blocked; 
 
 
 wherein the stator central cavity is configured to receive the cartridge; and 
 wherein the at least one cartridge aperture is positioned to be aligned with the stator aperture such that a flow path is established through the stator aperture between the housing interior space and the sensor located within the cartridge central recess; 
 wherein the base retaining device comprises:
 a split ring including a split; 
 a bayonet pin located along an exterior surface of the cartridge; and 
 a slot positioned on an interior surface of the stator and configured to receive the bayonet pin, the geometry of the slot configured to allow the cartridge to rotate through a predetermined angle within the stator, such that:
 in the flow position, the cartridge is retained within the housing; and 
 in a removal position, the bayonet pin aligns with an opening in the slot and the split in the split ring, allowing the cartridge to be removed from the housing. 
 
 
 
     
     
       2. The sensor assembly of  claim 1 , further comprising:
 a seal located on an exterior surface of the stator and positioned to engage the housing, wherein the seal is configured to limit fluid flow between the interior cavity and the housing interior space to occurring through the stator aperture. 
 
     
     
       3. The sensor assembly of  claim 1 , wherein the stator additionally includes at least one vent valve positioned along a portion of the stator projecting outwardly through an opening in an end wall of the housing and the vent valve is configured to allow air within the housing to vent through the vent valve. 
     
     
       4. The sensor assembly of  claim 1 , wherein the sensor assembly is configured such that:
 when the cartridge is positioned in the flow position, the stator is located in the open position; and 
 as the cartridge is rotated from the flow position towards the removal position, the stator is rotated along with the cartridge such that the stator reaches the closed position and, prior to the cartridge reaching the removal position, the flow path between the interior cavity and the stator central cavity through the stator aperture and the housing aperture is blocked. 
 
     
     
       5. The sensor assembly of  claim 1 , further comprising a compression member positioned between the stator and the cartridge, the compression member configured to bias the cartridge away from an end wall of the housing and toward the base retaining device. 
     
     
       6. The sensor assembly of  claim 1 , wherein the housing includes a stop to limit a rotational range of the stator with respect to the housing. 
     
     
       7. The sensor assembly of  claim 1 , wherein the sensor outputs data via a wired connection, wherein the wired connection includes a transmission wire passing directly from the sensor assembly to the interior cavity or the exterior. 
     
     
       8. The sensor assembly of  claim 1 , wherein:
 a position of the housing within the opening in the wall separating the interior cavity and the exterior is maintained by a fastener; and 
 an exterior surface of the housing is threaded and configured to engage with a threaded interior surface of the fastener. 
 
     
     
       9. The sensor assembly of  claim 1 , further comprising an end cap, wherein the end cap is configured to cover the opening in the wall when inserted such that an exterior surface of the end cap and the wall are essentially flush. 
     
     
       10. An aircraft comprising a fuel tank and the sensor assembly of  claim 1  installed in an opening in a wall of the fuel tank separating an interior cavity of the fuel tank from an exterior of the fuel tank. 
     
     
       11. A sensor assembly used to measure a fuel quantity of an aircraft, the sensor assembly installed in an opening in a wall of an aircraft separating an interior cavity of an aircraft fuel tank from an exterior, the sensor assembly comprising:
 a cartridge; 
 a housing including a housing interior space, the housing configured to be received within the opening in the wall such that at least one housing aperture in a wall of the housing communicates with the interior cavity, wherein the housing aperture is configured such that:
 a fluid flow path allowing fuel to pass from the interior cavity, through the housing aperture, and into the housing interior space is blocked when the cartridge is not positioned within the housing interior space; and 
 the fluid flow path allowing fuel to pass from the interior cavity, through the housing aperture, and into the housing interior space is established when the cartridge is positioned in a flow position within the housing interior space; 
 
 wherein the cartridge is configured to be received within the housing and includes:
 at least one pressure sensor supported within a central recess of the cartridge, wherein the at least one pressure sensor outputs pressure data regarding a pressure of fuel located within the aircraft fuel tank; and 
 at least one cartridge aperture positioned such that a fluid flow path of fuel through the cartridge aperture is established between the housing interior space and the sensor when the cartridge is positioned within the housing interior space; 
 
 a base retaining device configured to retain the cartridge within the housing; and 
 an end cap, wherein the end cap is configured to cover the opening in the wall when inserted such that an exterior surface of the end cap and the wall are essentially flush; 
 a stator disposed within the housing and rotatable between a closed position and an open position, the stator including:
 a central cavity; and 
 a stator aperture through a sidewall of the stator, the stator aperture located such that:
 in the open position, the stator aperture is in alignment with the housing aperture such that a flow path is established between the interior cavity and the stator central cavity; and 
 in the closed position, the stator aperture is out of alignment with the housing aperture such that the flow path between the interior cavity and the stator central cavity through the stator aperture and the housing aperture is blocked; 
 
 
 wherein the stator central cavity is configured to receive the cartridge; and 
 wherein the at least one cartridge aperture is positioned to be aligned with the stator aperture such that a flow path is established through the stator aperture between the housing interior space and the sensor located within the cartridge central recess; 
 wherein the base retaining device comprises:
 a split ring including a split; 
 a bayonet pin located along an exterior surface of the cartridge; and 
 a slot positioned on an interior surface of the stator and configured to receive the bayonet pin, the geometry of the slot configured to allow the cartridge to rotate through a predetermined angle within the stator, such that:
 in the flow position, the cartridge is retained within the housing; and 
 in a removal position, the bayonet pin aligns with an opening in the slot and the split in the split ring, allowing the cartridge to be removed from the housing.